Peroxisome Proliferator Activated Receptors (PPARs) are members of the nuclear hormone receptor super family, which are ligand-activated transcription factors regulating gene expression. Certain PPARs play roles in the regulation of cell differentiation, development and metabolism of higher organisms.
Three types of PPAR has been identified: alpha, expressed in the liver, kidney, heart and other tissues and organs, beta/delta expressed for example in the brain, and gamma, expressed in three forms: gamma1, gamma2, and gamma3. PPARγ receptors have been associated with stimulation of keratinocyte differentiation, and has served as a potential drug target for a number of disease states including skin disorders such as psoriasis and atopic dermatitis. Further, PPAR expression has been shown in hair follicles, and may be involved in hair growth.
Hair loss is a common problem, which can be the result of illness, functional disorder, or hereditary disposition. In some cases, hair loss can be localized on the body (e.g. male pattern baldness), or can occur body-wide. Alcopecia is a medical term for the absence or loss of hair, and can occur in patients undergoing treatment for cancer or for other diseases that require treatment with cytotoxic drugs.
De-pigmentation of hair is also a common problem, and is typically a result of the aging process. At some point in the aging process, stem cells at the base of hair follicles responsible for producing melanocytes (cells that produce and store pigment) produce less pigment, until the hair has little pigment.
Accordingly, effective agents, such as PPAR modulators, that are useful in the treatment of such hair disorders are needed.